If what Dimitri suggested is working for you, chances are you have Acrobat Pro - the audit tool is only available in Pro, which is also true for the Save as Optimized PDF function. If you have Acrobat Standard, your only way of decreasing the file size is by selecting Save As Other>Reduced Size PDF, which does not give you any options, it will just use it's built-in configuration. You will end up e.g. with downsampled images, but you don't have any control over how much or how little image quality you will have to give up.
Karl Heinz Kremer
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